This invention generally relates to the recycling and use of waste shingles, tar paper and portions thereof, and more specifically to an apparatus method and use for reduced shingle materials as a patch for potholes and a paving for roads, drives, walkways and the like.
Methods and apparati for manufacturing asphalt paving compositions for roadways and the like are well known. Typically, virgin aggregate is heated and dried in a rotating drum and then mixed with liquid asphalt in a proportion typically of five to six percent asphalt by weight. The paving composition is then hauled with trucks to the job site and dumped into a paving vehicle. The paver lays the hot mix out level to a desired thickness on top of a graded gravel surface of a suitable elevation and smoothness. Thereafter the new pavement is compacted with a roller to the desired density.
Commercial asphalt paving composition plants have a variety of problems. Asphalt plants are complex in that they require scales, tumble dryers, conveyors, furnaces, mixers, huge tanks for heating oil and asphalt oil and complex pollution control systems for controlling dust and emissions. Consequently, asphalt plants are stationary and not easily movable.
Roofing materials, including shingles, tar paper and portions thereof, also utilize asphalt. The asphalt is commonly an asphalt-concrete oil (AC Oil) which is heavy and tar-like. FIG. 1 schematically shows in cross section the composition of shingles 10. Shingles 10 begin with a mat 12 which may either be fiberglass or of a paper felt-like material. Initially the mat 12 is soaked with a light saturine oil 14. Thereafter, a layer of asphalt-concrete oil 16 is applied thereto. Next a layer of lime dust 18 is placed or dusted thereon. Another layer of AC Oil 20 is applied afterwhich a rock layer 22 is applied. Thereafter, the entire composition is run through rollers.
Considerable waste is associated with the manufacture of new shingles, which may approximate one hundred million squares annually. A square is one hundred square feet of shingles. Each shingle has three tabs cut out. Each cutout tab measures one-quarter inch by five inches. The three discarded tabs represent approximately two and a half percent of each new shingle which is discarded. When old shingles and tar paper are removed from old construction, the one to three layers of shingles are all considered waste and are to be disposed of. Thus old shingle materials represent an even larger amount of waste associated with shingle materials.
Methods and apparati exist by which old shingles and shingle material can be recycled, such as those shown in U.S. Pat. Nos. 4,222,851; 4,706,893; and 4,726,846. The '893 patent shows a method and apparatus wherein recycled shingles may be used in an asphalt plant mixed with heated and dried aggregate and liquid asphalt to form an asphalt paving composition. However, this method and apparatus has not been commercially successful due to its inability to handle shingles without clogging or plugging up.
Shingle materials by their very nature pose a complex problem in their reduction for recycling. The shingle materials, including the rock and asphalt oil in a range of twenty to thirty percent, are extremely heavy, sticky and abrasive. Efforts to reduce the shingle materials to particles and granules in hammermills have met with the clogging, plugging and sticking of the particles and granules within the hammermill, shutting down the production and necessitating maintenance and cleaning. Consequently, no one has reduced shingle materials to a small enough size that will permit their use alone or within an asphalt plant.
There is a need for a portable apparatus and method for reducing shingles down to a granular level in mass quantities of several hundred tons per day. The granular shingle materials may then be heated to create a patch for potholes and cracks, as well as a paving for roadways, walkways, driveways and the like without the need for a complex and polluting asphalt plant.